doi: 10.1161/CIRCULATIONAHA.107.707133
(Circulation. 2007;116:e93.)
© 2007 American Heart Association, Inc.
Correspondence |
Response to Letter Regarding Articles, "Prevalence of Long QT Syndrome Gene Variants in Sudden Infant Death Syndrome," "Cardiac Sodium Channel Dysfunction in Sudden Infant Death Syndrome," and "Contribution of Long-QT Syndrome Genes to Sudden Infant Death Syndrome: Is It Time to Consider Newborn Electrocardiographic Screening?"
Department of Cardiology, IRCCS Fondazione Policlinico S. Matteo, University of Pavia, Pavia, Italy
Departments of Medicine and Pharmacology, Vanderbilt University, Nashville, Tenn
The letter by Dr O’Rourke does not address correctly the findings and implications of our work on sudden death in infants that began in 1976.1 As recently specified elsewhere,2 we have repeatedly proposed a widespread ECG screening in the first month of life with the specific goal of early identification of infants affected by the long QT syndrome (LQTS). We never proposed it with the sole goal of prevention of sudden infant death syndrome, a naïve idea given that sudden infant death syndrome is multifactorial.3 Our objective has always been the prevention of sudden death caused by LQTS at whatever age it may occur. We and others4–7 have progressively demonstrated that a significant percentage of sudden infant death syndrome cases (9.5%; 95% CI, 5.8 to 14.4) are actually caused by LQTS, a highly treatable arrhythmogenic disease of genetic origin. It follows that neonatal ECG screening may allow prevention of these very early LQTS deaths, usually labeled as sudden infant death syndrome.
Contrary to what Dr O’Rourke infers, LQTS deaths are indeed caused by ventricular fibrillation independent of the age of the patients. This is not an assumption. The evidence that lethal arrhythmias underlie LQTS deaths is simply overwhelming. Also contrary to Dr O’Rourke’s statement, we did not "liken [LQTS] to ischemic and other heart diseases". The rhythm found by the ambulance services, when called for a cardiac arrest, depends on the time elapsed from the onset of the episode, and after several minutes ventricular fibrillation is followed by asystole. Dr O’Rourke’s abstract,8 published in 1998 but never followed by a full-length article, did not provide the mean time between cardiac arrest and ECG recording in his study. On the other hand, in a "proof-of-concept" case of cardiac arrest in an apparently healthy infant, later found to have a SCN5A mutation that caused LQTS,4 ventricular fibrillation was documented only because the family lived 100 yards from the local hospital.
Dr O’Rourke lumps ECG together with genetic screening. Neither we nor anyone else ever proposed "mass genetic screening" in newborns. In a recently completed prospective ECG study in 45 000 infants 3- to 4-weeks old, we demonstrated that 50% of those with a QTc >470 ms are LQTS mutation carriers.9 This means that the old, simple, inexpensive ECG may help select the few (<1/1000) infants in whom genetic screening would be rational.
As for health authorities, they wisely realize that neonatal ECG screening aims to prevent ventricular fibrillation in young adults, children, and adolescents, as well as in some infants. Currently, health authorities are carefully considering the implications of the high cost-effectiveness, at least in Europe, of such a screening.10
Although a program of neonatal screening may or may not be supported by individual physicians, our data leave no doubts as to the absolute right of parents of a newborn child to be informed about LQTS, an uncommon (1/2500 live births) but life-threatening disease, which is highly treatable and can be diagnosed by a simple ECG. Parents will then have the free choice to decide whether or not they wish carry out this act of cardiovascular prevention.
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Acknowledgments |
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Disclosures
None.
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References |
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 Top References |
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1. Schwartz PJ. Cardiac sympathetic innervation and the sudden infant death syndrome: a possible pathogenetic link. Am J Med. 1976; 60: 167–172.[CrossRef][Medline] [Order article via Infotrieve]
2. Schwartz PJ. Newborn ECG screening to prevent sudden cardiac death. Heart Rhythm. 2006; 3: 1353–1355.[CrossRef][Medline] [Order article via Infotrieve]
3. Schwartz PJ. The quest for the mechanism of the sudden infant death syndrome: doubts and progress. Circulation. 1987; 75: 677–683.
4. Schwartz PJ, Priori SG, Dumaine R, Napolitano C, Antzelevitch C, Stramba-Badiale M, Richard TA, Berti MR, Bloise R. A molecular link between the sudden infant death syndrome and the long QT syndrome. N Engl J Med. 2000; 343: 262–267.
5. Schwartz PJ, Priori SG, Bloise R, Napolitano C, Ronchetti E, Piccinini A, Goj A, Breithardt G, Schulze-Bahr E, Wedekind H, Nastoli J. Molecular diagnosis in a child with sudden infant death syndrome. Lancet. 2001; 358: 1342–1343.[CrossRef][Medline] [Order article via Infotrieve]
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8. Adelstein BA, O’Rourke MF, Hall J, Love A: Out-of-hospital VF in children: frequency and outcome. Circulation. 1998; 98 (suppl 1): I-410.
9. Goulene K, Stramba-Badiale M, Crotti L, Priori SG, Salice P, Mannarino S, Rosati E, Schwartz PJ: Neonatal electrocardiographic screening of genetic arrhythmogenic disorders and congenital cardiovascular diseases: prospective data from 31 000 infants. Eur Heart J. 2005; 26 (suppl): 214. Abstract.
10. Quaglini S, Rognoni C, Spazzolini C, Priori SG, Mannarino S, Schwartz PJ. Cost-effectiveness of neonatal ECG screening for the long QT syndrome. Eur Heart J. 2006; 27: 1824–1832.
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